Technical Field
[0001] The present invention relates to a paper roll production apparatus for use in production
of large paper rolls.
Background Art
[0002] Producing recycled paper by using wastepaper may involve the following. The wastepaper
is transformed into pulp, which is then defibrated in water to obtain, for example,
white water. Subsequently, paper stock is strained from the white water with a fourdrinier
wire screen or a cylinder wire screen and undergoes a dewatering process and a drying
process. Consequently, large paper rolls having, for example, a desired degree of
flexibility and a desired degree of strength are produced (see, for example, PTL 1).
[0003] The production time per roll is particularly longer for large paper rolls such as
parent rolls. It is thus desired that each production process be conducted as fast
as possible. A suction former or the like speedily conducts sheet forming and dewatering
processes, and some other apparatuses speed up the subsequent processes such as drying
and roll-winding processes have been developed.
Citation List
Patent Literature
[0004] PTL 1: Japanese Patent No.
5288480
Summary of Invention
Technical Problem
[0005] The aforementioned sheet forming needs to be performed in such a manner as to produce
soft-touch paper with a desired degree of strength, which may be achieved through,
for example, a uniform fiber orientation. It is thus required that the paper stock
strained with, for example, a cylinder wire screen be formed into a sheet and be dried
in such a manner as to have, for example, a uniform fiber orientation. Thus, a suction
former designed to operate at a relatively low speed is used in a production apparatus.
[0006] Alternatively, a suction former capable of operating at a high speed may be used
to shorten the production time for large paper rolls. In this case, paper fibers may
be in random orientations at the time of removal of water, and flexibility of the
resultant paper under dry conditions may be hampered.
[0007] Thus, producing paper in large quantity and in the shortest possible time requires
the use of, for example, different suction formers for different intended paper qualities.
Thus, different production apparatuses having different configurations are to be installed.
This will result in increases in the cost of installation and maintenance, and a considerable
amount of installation space is necessary.
[0008] The present invention has been made in view of these problems, and it is an object
of the present invention to provide a paper roll production apparatus that saves installation
space and enables production of paper rolls of different qualities and a shortening
of production time.
Solution to Problem
[0009] A paper roll production apparatus according to the present invention includes: a
first sheet-forming machine and a second sheet-forming machine for forming paper stock
into a sheet and for dewatering the paper stock; a drying machine for dying the paper
stock dewatered by the first or second sheet-forming machine to from a dry paper material;
a switching mechanism part for switching to feed, into the drying machine, the paper
stock dewatered by the first sheet-forming machine or the paper stock dewatered by
the second sheet-forming machine; and
a winder for winding up the dry paper material provided by the drying machine to form
a paper roll. The first sheet-forming machine operates at a sheet-forming speed at
which a fiber orientation of the paper stock is maintained. The second sheet-forming
machine operates at a sheet-forming speed faster than the sheet-forming speed of the
first sheet-forming machine. The winder winds up the dry paper material at a speed
corresponding to the sheet-forming speed of the first sheet-forming machine or to
the sheet-forming speed of the second sheet-forming machine to form the paper roll.
[0010] The second sheet-forming machine includes: a suction former operating at a sheet-forming
speed faster than the sheet-forming speed of the first sheet-forming machine; and
a conveyor part for conveying, to the drying machine, paper stock dewatered by the
suction former. The second sheet-forming machine is disposed above the first sheet-forming
machine with a difference in elevation between the first and second sheet-forming
machines, the difference being provided to remove, from the paper stock, water in
an amount corresponding to the sheet-forming speed of the suction former when the
conveyor part conveys the paper stock dewatered by the suction former.
Advantageous Effects of Invention
[0011] According to the present invention, large paper rolls are produced in such a manner
that the choice of which suction former to use may be determined in accordance with
the intended paper quality. The present invention thus saves installation space and
reduces production time to the maximum extent possible.
Brief Description of Drawings
[0012]
Fig. 1 illustrates a schematic configuration of a paper roll production apparatus
according to an example of the present invention.
Fig. 2 illustrates a schematic configuration of a sheet-forming and dewatering part
of the paper roll production apparatus illustrated in Fig. 1. Description of Embodiments
[0013] The following describes, with reference to the accompanying drawings, an example
that is an embodiment of the present invention.
(Example)
[0014] Fig. 1 illustrates a schematic configuration of a paper roll production apparatus
according to an example of the present invention. This illustrates the configuration
of a production apparatus 1, which produces large paper rolls such as parent rolls
from pulp containing, for example, wastepaper dissolved therein. A device for transforming,
for example, wastepaper into pulp, a device for defibrating the pulp in water to generate
white water, and a device or equipment for feeding the white water into a sheet-forming
and dewatering part 5 are not illustrated in the drawing.
[0015] The production apparatus 1 is installed in a building of, for example, a plant and
is fixed to a floor surface 2 of the building. The production apparatus 1 includes:
the sheet-forming and dewatering part 5, which draws paper stock from white water
and dewaters the paper stock; a drying machine 6, which dries the paper stock dewatered
by the sheet-forming and dewatering part 5; and a winder 8, which forms, for example,
a parent roll 4 by winding up the paper material dried by the drying machine 6.
[0016] Part of the floor surface 2 located below the sheet-forming and dewatering part 5
has a drainage trench 3, through which droplets of water removed during the sheet
forming or dewatering process are transported to a predetermined site.
[0017] The drying machine 6 includes a Yankee dryer 6a which sticks the paper stock coming
out of the sheet-forming and dewatering part 5 on the surface of the Yankee dryer
6a. A doctor 8 is disposed on a lower end portion of the Yankee dryer 6a to scrape
the paper material sticking on the surface of the Yankee dryer 6a. The production
apparatus 1 also includes a conveyor that conveys the paper material scraped by the
doctor 8 to the winder 8.
[0018] Fig. 2 illustrates a schematic configuration of the sheet-forming and dewatering
part of the paper roll production apparatus illustrated in Fig. 1. The sheet-forming
and dewatering part 5 illustrated in Fig. 2 includes: a first sheet-forming machine
11 having a suction former 22 for low-speed dewatering; and a second sheet-forming
machine 12 having a suction former 32 for high-speed dewatering. The sheet-forming
and dewatering part 5 also includes a switching mechanism part 13 having a++ touch
roll in contact with, for example, a lower portion of the Yankee drum 6a.
[0019] The sheet-forming and dewatering part 5 is provided in such a manner that the first
sheet-forming machine 11 is fixedly installed on the floor surface 2 and the second
sheet-forming machine 12 is fixedly installed above the first sheet-forming machine
11 with a frame member or a mounting member (not illustrated).
[0020] The first sheet-forming machine 11 is configured to lay, on a first transfer felt
20, paper stock drawn by the suction former 22. The first transfer felt 20 is supported
by, for example, a plurality of rollers in such a manner as to move circularly between
the touch roll of the switching mechanism part 13 and the suction former 22. The first
transfer felt 20 is installed in such a manner as to be connected to (in contact with),
for example, a drive unit (not illustrated) that causes the first transfer felt 20
to move circularly as described above.
[0021] The second sheet-forming machine 12 is configured to lay, on a second transfer felt
30, paper stock drawn by the suction former 32. The second transfer felt 30 is supported
by, for example, a plurality of rollers in such a manner as to move circularly between
the touch roll of the switching mechanism part 13 and the suction former 32. The second
transfer felt 30 is installed in such a manner as to be connected to (in contact with),
for example, a drive unit (not illustrated) that causes the second transfer felt 30
to move circularly as described above.
[0022] The switching mechanism part 13 is provided so that the paper stock laid on the first
transfer felt 20 or the paper stock laid on the second transfer felt 30 is stuck to
the Yankee dryer 6a. For example, the switching mechanism part 13 is configured to
change the first transfer felt 20 and the second transfer felt 30 to let either of
these transfer felts to contact the touch roll such that either of these transfer
felts comes into contact with the Yankee dryer 6a to stick the dewatered paper stock
on the surface of the Yankee dryer 6a.
[0023] The second sheet-forming machine 12 is disposed above the first sheet-forming machine
11. Thus, the second transfer felt 30 moves at higher elevations than the first transfer
felt 20. The second transfer felt 30 is provided in such a manner as to have a steep
gradient and to move circularly between sites with a large difference in elevation.
[0024] Specifically, the second transfer felt 30 is provided and configured as follows.
The second transfer felt 30 moves circularly between the touch roll of the switching
mechanism part 13 and the suction former 32 disposed at an elevation higher than the
elevation at which the touch roll is disposed. Owing to, for example, the high elevation
and the given gradient of the second transfer felt 30, the paper stock laid on the
second transfer felt 30 is dewatered with a high degree of efficiency, or water squeezed
out from the paper stock drains downward.
[0025] The first transfer felt 20 and the second transfer felt 30 are supported by, for
example, the rollers as described above. Paths on which the corresponding transfer
felts move provide press parts that dewater paper stock formed into a sheet or extract
water from the paper stock under pressure.
[0026] The first sheet-forming machine 11, which operates at a low sheet-forming speed,
is configured as follows. At a headbox 21, paper stock formed into a sheet in, for
example, a wire part is laid on the first transfer felt 20. The paper stock is then
brought into contact with, for example, a press roll of the suction former 22 adjacent
to the headbox 21, where the paper stock on the first transfer felt 11 is dewatered
or undergoes water extraction under pressure. Consequently, most of water is removed
from the paper stock.
[0027] The second sheet-forming machine 12, which operates at a high sheet-forming speed,
is configured as follows. At a headbox 31, paper stock formed into a sheet is laid
on the second transfer felt 30. The paper stock is then brought into contact with,
for example, a press roll of the suction former 32 adjacent to the headbox 31, where
the paper stock on the second transfer felt 30 is dewatered or undergoes water extraction
under pressure.
[0028] The first sheet-forming machine 11 operates at a sheet-forming speed of, for example,
900 (m/min) or lower. The second sheet-forming machine 12 operates at a sheet-forming
speed of, for example, 1,800 (m/min) or higher.
[0029] The sheet forming and dewatering at the headbox 31 is conducted in such a manner
as to enable the second sheet-forming machine 12 to achieve a given sheet-forming
speed. When the sheet-forming speed is higher, it is more difficult to take enough
time to dewater paper stock.
[0030] As illustrated in, for example, Fig. 2, the second sheet-forming machine 12 of the
production apparatus 1 is disposed above the first sheet-forming machine 11 of the
production apparatus 1.
[0031] Thus, the headbox 31 and the suction former 32 may be disposed at high elevations
and may be sparsely surrounded by other structures accordingly. When the paper stock
drawn from white water is dewatered, water droplets squeezed out from the paper stock
can be spattered in an efficient manner.
[0032] The second transfer felt 30 is disposed between the suction former 32 at a high elevation
and the drying machine 6 at a low elevation or between the suction former 32 and the
switching mechanism part 13 and is inclined or has a difference in elevation between
the highest and lowest points accordingly.
[0033] When paper stock is laid on the second transfer felt 30 and is conveyed along, for
example, the inclined part, water contained in the paper stock drains downward. That
is, moisture in the paper stock dewatered by, for example, the suction former 32 may
be further reduced.
[0034] The second sheet-forming machine 12, which operates at a high sheet-forming speed,
is disposed at a high elevation with a predetermined difference in elevation between
the first sheet-forming machine 11 and the second-sheet-forming machine 12. Owing
to this configuration of the production apparatus 1, paper stock that is to be conveyed
to the drying machine 6 may be sufficiently dewatered during operation of the first
sheet-forming machine 11 or the second sheet-forming machine 12, that is, during operation
conducted at any sheet-forming speed.
[0035] The difference in elevation between the second sheet-forming machine 12 and the first
sheet-forming machine 11 is set in accordance with the sheet-forming speed of the
second sheet-forming machine 12 or the sheet-forming speed of the suction former 32.
In light of the fact that the dewatering time of, for example, the suction former
32 decreases with increasing sheet-forming speed, the suction former 32 is disposed
at an elevation high enough to be sparsely surrounded by other structures, and water
droplets can be spattered in an efficient manner accordingly. The second transfer
felt 30, which conveys the paper stock, is inclined or has a difference in elevation
between the highest and lowest points so that a sufficient amount of water can be
removed from the paper stock.
[0036] The drying machine 6 or the Yankee dryer 6a is configured to dry paper stock conveyed
to the touch roll of the switching mechanism part 13. Specifically, paper stock formed
into a sheet and dewatered by the first sheet-forming machine 11 or the second sheet-forming
machine 12 is stuck on the surface of the Yankee dryer 6a, which is heated by, for
example, a heater to dry the paper stock. That is, the drying machine 6 dries, under
high temperature conditions, paper stock conveyed by the first transfer felt 20 or
the second transfer felt 30, whichever is attached to the touch roll of the switching
mechanism part 13.
[0037] The drying machine 6 is configured to operate at a drying speed corresponding to
the sheet-forming speed of the first sheet-forming machine 11 or to the sheet-forming
speed of the second sheet-forming machine 12. The Yankee dryer 6a is configured to
operate at a rotation speed corresponding to the speed at which the first transfer
felt 20 or the second transfer felt 30 moves.
[0038] When the moisture content of the paper stock dewatered by the first sheet-forming
machine 11 differs from the moisture content of the paper stock dewatered by the second
sheet-forming machine 12, the inner temperature of the drying machine 6 (the surface
temperature of the Yankee dryer 6a) and the like may be adjusted in accordance with
the dewatered state of the paper stock concerned.
[0039] The paper material dried by the Yankee dryer 6a is then scraped off the surface of
the Yankee dryer 6a by the doctor 7 illustrated in Fig. 1 and is formed into wide
paper. The production apparatus 1 causes the winder 8 to wind up the wide paper to
form into the roll paper 4.
[0040] The winder 8 is configured to wind up wide paper at a speed corresponding to the
speed at which the wide paper comes out of the Yankee dryer 6a. Specifically, the
winder 8 is configured to operate in such a manner that a wide tape made of a paper
material formed by the second sheet-forming machine 12 is wound up at a speed faster
than the speed at which wide paper made of a paper material formed by the first sheet-forming
machine 11 is wound up.
[0041] This configuration enables changing of the sheet-forming speed to produce paper rolls
of desired paper qualities, and in particular, to produce large paper rolls in the
shortest possible time. The production apparatus saves installation space.
[0042] The second sheet-forming machine 12, which operates at a high sheet-forming speed,
is disposed above the first sheet-forming machine 11 with a predetermined difference
in elevation between these sheet-forming machines. This configuration enables sufficient
dewatering of paper stock irrespective of whether the first sheet-forming machine
11 or the second sheet-forming machine 12 is used.
Reference Signs List
[0043]
- 1
- production apparatus
- 2
- floor surface
- 3
- drainage trench
- 4
- parent roll
- 5
- sheet-forming and dewatering part
- 6
- drying machine
- 6a
- Yankee dryer
- 7
- doctor
- 8
- winder
- 11
- first sheet-forming machine
- 12
- second sheet-forming machine
- 13
- switching mechanism part
- 20
- first transfer felt
- 21
- headbox
- 22
- suction former
- 30
- second transfer felt
- 31
- headbox
- 32
- suction former